Pneumatic handling system for particulate material



Jan. 30, 1968 E. BARBER 3,366,277

PNEUMATIC HANDLING SYSTEM FOR PARTICULATE MATERIAL Filed June 17, 1966 3Sheets-Sheet 1 Ea. A

Jan. 30, 1968 v E. A. BARBER PNEUMATIC HANDLING SYSTEM FOR PARTICULA TEMATERIAL Filed June 17, 1966 3 Sheets-Sheet 2 INVENTOR. 964? 0. $4 568Jan. 30, 1968 E. A. BARBER 3, ,2 7

PNEUMATIC HANDLING SYSTEM FOR PARTICULATE MATERIAL Filed June 17, 1966 3Sheets-Sheet 5 f u m? INVENTOR. ame A). Meaae United States Patent3,366,277 PNEUMATIC HANDLING SYSTEM FOR PARTICULATE MATERIAL Edgar A.Barber, Newaygo, Mich., assignor to Newaygo Engineering Company,Newaygo, Mich., a corporation of Michigan Continuation-impart ofapplication Ser. No. 477,67 7,

Aug. 6, 1965. This application June 17, 1966, Ser.

Claims. (Cl. 222-70) ABSTRACT OF THE DISCLOSURE Granular materialfluidizing and transporting apparatus employing in combination with ahopper, a fluidizing chamber, and material inlet valve means, a specialarrangement of a specifically located and configurated fluidizing nozzleapparatus in combination with the inlet valve and with a specificallylocated and operated material discharge, all controlled to effectinstantaneous, swirling fluidizing and discharge, preferably incombination with a special venting system.

This is a continuation-in-part application of copending patentapplication entitled Pneumatic Sand Transporter, Ser. No. 477,677 andfiled Aug. 6, 1965.

This invention relates to apparatus for pneumatically transportinggranular or powdered material from one location to another, and moreparticularly relate-s to apparatus for pneumatically fluidizing andconveying materials such as foundry sand, bentonite, iron oxide, fireclay, sea coal, paint pigment, and most other flour-like or particulateand granular materials.

.Since this apparatus was developed initially for handling foundry sand,it will largely be explained in relation thereto for convenience.However, the apparatus can be used for other materials like those noted.It is particularly useful, however, for sand since it contrasts sharplywith all other prior attempts to convey sand in an upward direction outof a chamber.

Since forging and casting plants utilize great quantities of sand whichmust be conveyed to many working stations, it is desirable that thissand be transported from a receiving station to the working locationsthroughout the foundry without utilizing valuable floor space such asworking aisles. Further, the sand should be conveyed rapidly anddependably to economically meet the demand of all work stations, yetwithout causing substantial air contamination with dust or the like.

Pneumatic sand conveying systems have been developed and usedheretofore, using a fluidizing action on the sand in order to obtainproper sand density in the flowing stream. However, most priorapparatuses have dropped the sand out of the bottom of a vessel withdownwardly convergent sides. One prior device which does not drop it outthe bottom in such that it requires a physical sand thruster plungingupwardly into the sand from the bottom to try to suspend it. Theinventor herein has devised a particular type of apparatus and systemthat enables granular materials such as sand or the like to actually bedependably discharged upwardly out of a chamber without the need for anoutlet from the bottom of the chamber and without the necessity of aphysical sand thruster with all of its problems and complications. Theinvention is keyed around the discovery that fluidizing can be achievedvery effectively with the use of a special type of fluidizing chamberand apparatus arrangement. This effective fluidizing action enablesdirect entrainment of the sand into the transporting gas without aninitial mechanical, mass displacement of the sand with physical meanssuch as a sand thrusting diaphragm or the like. This greatly simplifiesthe equipment, reducing both initial and maintenance costs andincreasing service life, thereby enabling such pneumatic sand conveyingequipment to be economically and practically available to relativelysmall and medium size foundry operations. It further increases theoutput of the conveying apparatus many times over that of knownapparatus of generally the same size. In fact, the novel equipment hasreceived tremendously enthusiastic reception by handlers of granularmaterial particularly small and medium size foundry men. The equipmenthas been ordered in great numbers by such foundries since it enablesthem to modernize their operations and economically compete moreeffectively. The novel equipment enables automatic operation and controlof a good share of the foundry operations, even though the operationsare relatively small. Further the minor expense required for replacementparts is tremendously small in comparison with other equipment.

Close observation of many of the units built according to the teachingsof the parent application have shown that additional features aredesirable to eliminate certain potential problems of the equipment. Morespecifically, firstly, it has been determined that sometimes certainmaterials such as sand do not drop from the hopper to the fiuidizerchamber of the novel apparatus, but rather tend to bridge across theinlet to the chamber, so as to prevent sand from being conveyed from thefluidizer. Secondly, it has been noted that use of the equipment toconvey sand containing resin powder (e.g. for shell molding or thelike), or to convey flour type materials, sometimes results inundesirable dust in the air near the hopper and fluidizer. Upon carefulanalysis of the equipment during experimentation and operation, theinventor discovered that both the bridging and the dust blow problemswere caused by certain residual pressure differential conditions and/ orcertain displacement air flow conditions.

It is one object of this invention to provide a granular fluidizing andconveying apparatus having relatively few moving parts, compactness,relatively low cost and maintenance requirements, and which is largelyadvantageous to small and medium size foundries to enable the operationsthereof to be automated.

It is another object of this invention to provide a granular fluidizingapparatus capable of conveying materials such as sand out the top of achamber but which does not require or employ displacement of the sandmass by any means other than the transporting air. It does not require aphysical plunger or diaphragm or the like to cause complications. Yetthe fiuidizer is so effective that, immediately upon actuation of thepneumatic fluidizer, the sand or other material is ready to be conveyedas a fluid.

It is another object of this invention to provide a novel fluidizingnozzle capable of effectively fluidizing granular material such as sandto a completely flowable state even though the latter lies on a fiatsurface and within an enclosed fluidizing chamber.

Another object of this invention is to provide a granular fluidizing andconveying apparatus having a unique relationship between the fluidizingchamber structure, a special fluidizing nozzle, and an upwardly orientedoutlet conduit for the fluidized material having its lower open endprotruding into the chamber.

Another object of this invention is to provide a novel sand fluidizingand conveying apparatus having means to prevent bridging of sanddropping into the fluidizing chamber of the apparatus.

Another object of this invention is to provide a novel sand fluidizingand conveying apparatus having means to prevent dust blowing into thesurrounding vicinity.

Another object of this invention is to provide a unique sand fluidizingand conveying apparatus having special pressure control means on thefluidizing chamber and capable of being programmed into automatic timedoperation.

These and other objects of this invention will become apparent by studyof the following specification in conjunction with the figures in which:

FIG. 1 is an elevational side view of the apparatus of this invention,with certain portions cut away;

FIG. 2 is an elevational front view of the apparatus in partialcross-section;

FIG. 3 is a fragmentary, enlarged, partially cross-sectioned elevationview of the fluidizing nozzle assembly;

FIG. 4 is a sectional view taken on plane IVIV of FIG. 3;

FIG. 5 is a vertical sectional view of the venturi unit on the outflowconduit;

FIG. 6 is a sectional view taken on plane VIVI of FIG. 5;

FIG. 7 is a side elevational view of the complete apparatus;

FIG. 8 is a schematic view of the control and operating circuit; and

FIG. 9 is a vertical sectional view of the vent valve assembly.

Referring now to the drawings, the assembly 11 includes the hopper 1,fluidizer chamber 10, inlet control valve assembly 30, fluidizing nozzleassembly 60, fluidized material outlet assembly 70, and vent valveassembly 90.

The hopper receives and temporarily stores granular material to bedischarged to the fluidizer. This hopper is composed of a vertical backwall 2, a downwardly inwardly slanted front wall 3, and downwardlyinwardly convergently slanted side walls 4.

Positioned below the hopper is fiuidizing chamber preferably formed witha vertical cylindrical peripheral wall 11, a top cover plate 12, and arigid bottom plate 13. The entire assembly rests on support 20 which maybe integral with the side wall.

The convergent bottom of hopper 1 is positioned above and communicateswith the top of the fiuidizing chamber through a passage throat 21. Theplunger valve assembly 30 is provided at throat 21 between the hopperand the top of the fiuidizing chamber. A downwardly flaring valve seat31 surrounds the throat. The plunger valve is shown in closed positionin solid lines and open position in phantom lines. The valve head 32 issuspended on vertical shaft 34 attached to the extending piston rod ofvertical control cylinder 50.

The closure valve head 32 of the plunger valve assembly is generallydome-shaped, having downwardly divergent walls. It may have a doubletaper as shown in FIGS. 1 and 2 or a conical shape as shown in FIG. 8.The walls of throat 31 are also downwardly divergent to cooperate withthe sides of the closure head when the latter is pulled up into theclosed position. This arrangement facilitates the operation of the valveby causing the sand to flow off the sides of the head as the valvecloses. It has another functional purpose as will be seen more fullyhereinafter.

A plunger valve cylinder housing indicated generally at 40 is providedwithin hopper 1. This housing is composed of wall members 41-46 toprotect the valve operating mechanism from the abrasive effects of thegranular material. Contained within the hopper is an L-shaped bracket 47to support cylinder 50. L-shaped bracket 47 has apertures (not shown)which shaft 34 passes and by means of which actuating cylinder 50 isrigidly positioned. The actuating cylinder 50 may be any type of primemover capable of exerting an up and down thrust, preferably, a two-wayair cylinder operated directly from air lines 51 and 52.

The fluidizing nozzle assembly 60 includes a special vertical standpipe62 and a cooperative hood 64. The cylindrical standpipe projects up fromthe chamber bottom at the center of the chamber. The standpipe positionsthe hood up within the fluidizing chamber, substantially spaced abovebottom panel 13, and centered under valve 30. The standpipe is suppliedwith compressed air by an inlet pipe 61 communicating with the bottom ofthe hollow standpipe and extending through support 20.

The details of the fluidizing nozzle assembly are best explained byreference to FIGS. 3 and 4. Adjacent the upper extremity of standpipe62, within the confines of hood 64 is located a plurality of generallyradial apertures 66 which are spaced around the standpipe at intervals,and project tangentially from the pipe interior to exterior to cause ahelical flow pattern in a manner to be described. It has been found, forexample, that a standpipe having an outside diameter of 1.125 inches andfour equally spaced quarter inch apertures will give satisfactoryresults. The fluidizing nozzle hood 64 is rigidly affixed to the upperextremity of standpipe 62, and has a depending annular skirt 68extending down around the upper end of the standpipe, beyond theorifices, slightly spaced from the standpipe and orifices to form anannular downwardly oriented air channel 65 around and below that portionof standpipe 62 containing apertures 66. An annular air channel with aradial width of 0.040 inches has been found satisfactory on thestandpipe mentioned above. The portion 68 of standpipe 62 preferably istapered slightly downwardly divergently along its length, the wider endabutting the floor of the fluidizing chamber. The above described nozzleassembly emits an annular air stream in the downward direction indicatedgenerally by arrows 67. The annular stream is necessary for effectivefluidizing. The helical air flow of the annular stream creates aswirling action in the chamber to fluidize the entire charge of materialtherein out to the chamber cylindrical wall, an asssits the migration ofthe material to the bottom inlet 74 of the outflow conduit. The annularair stream flares radially inwardly and outwardly as it emerges fromannular channel 65, to sweep around the base of the standpipe and tosweep outwardly to be effective at the annular corner junction of thegenerally horizontal bottom 13 and wall 11. This is very important inthis construction for effective fluidizing and material flow. It hasbeen found that the lower outlet of channel 65 may be inclined radiallyoutwardly at a small acute angle to the vertical but the angle should besmall, if used, since the material should not enter apertures 66 whenthe fluidizer is shut ofi, since the flared air flow pattern shouldsweep around the base of the standpipe, and since the optimum helicalpattern is then obtained.

The fluidized sand outlet assembly, indicated generally by referencenumeral 70, includes a downwardly open inlet 74- in lower conduit 75projecting into fiuidizing chamber, a check valve chamber 71, valve seat72, a pressure responsive ball check valve 73, and an upper conduit 76extending up above the fluidizing chamber to communicate at 77 to otherconduit means (not shown) to transport the entrained sand to the pointsof demand. The lower conduit 75 extends sufficiently into fluidizingchamber 10 so that port 74 is located well below the bottom of flange 68of air nozzle 64. Port 74 should be sufficiently close to bottom 13 toobtain optimum negative pressure at this point, such negative pressurebeing caused in the conduit by venturi unit 80. Maximum negativepressure at this point 74 occurs when the spacing of it from bottom 13is such that the planar area of port 74 equals the cylindrical area ofthe space between end 74 and bottom 13. However, it has been found thatif the port 74 is this close to bottom 13, the material flow path tendsto be restricted slightly. Therefore, it has been determined that if thecylindrical flow area noted is made to equal about 1.25 that of theplanar area of port 74, an optimum compromise is reached at whichmaterial output flow is maximized.

Enclosed wit-bin enlarged diameter valve chamber 71 is a ball checkvalve 73. The ball valve sits against lower seat 72 when not elevated bythe fluidized sand. When ball 73 is elevated it is prevented fromsealing by abutting a cross stop pin extending across valve chamber 71.Attached to the upper portion of the valve chamber is upper conduit 76,It may be stabilized by being secured to the hopper by suitablefastening brackets 78.

On conduit section 76 is a venturi unit 86 that cooperates with thesystem as a booster conveyor and as a primary conveyor. That is when thefluidizer is operating, the unit 80 creates a negative pressure at 74 topull the fluidized material from the fluidizing chamber and pushes it upthe conduit; and when the fluidizer is shut off, and check valve 73closes, unit 813' acts as a prime conveyor of the fluidized material inconduit 76 and the conduits (not shown) downstream thereof. This isexplained in more detail hereinafter. The combination of all of theseelements achieves dependable, rapid material flow even though thefluidizing chamber is at a relatively low positive pressure and thematerial is moving in it at a relatively low velocity.

The details of construction of the Venturi unit 80 are shown mostclearly in FIGS. 5 and 6. The unit is inserted and fastened to conduit76 by appropriate connectors 134. The unit includes a pair of end pieces135 and 137 held together by bolts 139. These end pieces clamp betweenthem a manifold assembly composed of three rings 141, 143 and 145,secured together by bolts 147 and defining an annular manifold chamber136. Compressed air is tangentially introduced into manifold chamber 136by tangential air intakes 138. The walls 148 and 156 of rings 141 and145 define between them a frustoconical nozzle 14-11 which opens intoconduit '76. It will be noted from FIG. 5 that the jet 80 isso-constructed that there is no discontinuity in conduit 5t] throughoutthe jet, except for the actual discharge opening of nozzle 140 itself.This construction significantly reduces the turbulence at jet 8t) andaids in the rapid creation of a smooth air cushion downstream, i.e. upconduit 76 from unit 80. Air is discharged in a spiraling laminarpattern from annular nozzle 140 and expands in the conveying pipe into adivergent pattern. The rapid forward motion and quantity of airdischarged from nozzle 140 creates a vacuum or negative pressureupstream of unit 80 which is transferred down to inlet 7-4 to draw thefluidized material up through the lower conduit section and pushes thematerial up through the upper conduit section. In order to compensatefor the convergence of the air stream at the exit from nozzle 141 thesurface of the imaginary cone C defined by nozzle 140 is disposed at a15 angle to conduit wall 152. The rapid spinning motion'of the airstream as it travels through the conduit quickly causes the convergenceforces to be overcome by the centrifugal forces action on the airmolecules, so that the air stream quickly settles into a cylindrical aircushion spiraling along forwardly on the walls of the conduit. The airis introduced into manifold 136 by intakes 138 in a manner to causecounter-clockwise spinning of the air emerging fromnozzle 140. This isthe natural spin direction in the Northern Hemisphere. If this spindirection is not observed, a reversal of the spin direction occurs inthe conduit at some distance downstream from unit 80 to possibly causeclogging, and to cause lowering of the efliciency'of the unit. For thesame reasons, the air outflow from nozzle assembly 61; is caused to movein a counter-clockwise direction, (looking down at the nozzle).

Another feature of the apparatus which enables rapid refilling of thefluidizing chamber on a cycled basis, and which prevents the dust blowproblem which was encountered with earlier units, is the controlledventing valve means 90. This venting valve means 9i} is communicant withfluidizing chamber 113 through conduit 92 and is communicant to theatmosphere through conduit 94. Valve means 98 is preferably of the typeshown in FIG. 9, in order to enable it to be sealed olf even though dustparticles may be retained in the air stream moving through it. Itpreferably comprises a resilient cylindrical bladder 91 having a pair ofradially extending peripheral end flanges 93. The housing of theassembly includes an annular rigid metal ring 95 having a centralcylindrical section, and a pair of radially extending peripheral endflanges to fit within the annular outer peripheral channel betweenflanges 93 of the bladder, and to encompass the cylindrical bladdersection 91. This annular member is secured to a pair of end couplingmembers 97 and 97. by suitable bolts 99. Coupling 97 connects to conduitM, and coupling 97' connects to conduit 92. A control air pressure line1111 extends through annular member 94 to be communicant with theoutside of bladder 91 so that, when air pressure is applied through thisconduit, the bladder is deformed inwardly as shown by the phantom linesin FIG. 9 to seal off the conduit.

The control system for the apparatus is illustrated in FIG. 8. Thiscontrol system is largely pneumatic, with certain of the valves beingcontrolled by timers. More specifically, the pressurized inlet conduit1% communicates with a manifold 1-02 which supplies pressurized air tothree main branch assemblies. Conduit 107 communicates through anormally open solenoid valve V1, through a pressure regulator 108 toVenturi unit 81!. Conduit 61 communicates through a solenoid valve V2,controlled by timer T3, through a pressure regulator 110 to fluidizernozzle assembly 60. Conduit 111 communicates through a four-way solenoidvalve 112 controlled by timer T1 and T2 for the down and up strokes ofcylinder 41}. The four-way solenoid valve communicates with inflow line111, its exhaust line, and with the upper and lower ends of cylinder asthrough conduits 51 and 52. A bleed-01f line 1151 is taken from conduit52 to the lower end of the cylinder, through pressure regulator 16,through vent valve assembly as, which controls the venting action fromfluidizing chamber 10.

When the apparatus is at rest, cylinder 40 is in its lowered position sothat valve head 32 is in its lowered open condition as shown in phantomlines in FIG. 1. Sand or other granular material in the hopper istherefore free to flow by gravity down into the fluidizing chamber.Normally, it fills the entire chamber except for a peripheral areaaround the upper outer portion, and except for a void spot which formsdirectly below the lower flat underside surface of valve head 32.

When the apparatus is actuated, valve V1 is normally constantly open sothat Venturi unit is always energized. Also, upon activation of theassembly, valve V2 is opened so that pressurized air can flow throughconduit 61 to fluidizer 60. Simultaneously, air pressure is allowed topass through solenoid valve 112 through the conduit to the lower end ofcylinder 40 to raise the cylinder rod and close valve head 32. It willbe realized that since the sand or other material has been allowed toflow freely into the fluidizing chamber over the surface of valve head32, a substantial amount of sand still rests on the upper surface ofvalve head 32. It also will be realized that sand normally acts as asolid material so that the valve head woud not be able to close, exceptthat the fluidizer is so instantaneously effective that it forms afluidized system of the entire charge in the fluidizing chamber, eventhe sand on top of valve head 32, so that the valve head can actually berammed up closed into a sealed condition practically instantaneouslyupon starting or activation of the system. When the valve head 32 isrammed upwardly into a closed position, the fluidized sand previouslyresting upon its upper surface flows down around the valve and into thecavity beneath the lower surface of the valve. Simultaneously, withactivation of the fluidizer and the cylinder, the bleed-off line 101allows a controlled amount of air pressure, controlled by regulator 116,to close vent valve by applying a peripheral pressure around bladder 91.After the sand becomes fluidized, it is swirled in the fluidizingchamber at a low velocity and under a slight positive pressure from thefluidizer nozzle. The negative pressure created at inlet 74 of theoutlet system causes the sand nearest this port to be entrained firstand sucked up through the conduit, opening the ball check valve 73, andflowing up past Venturi unit 80 which is constantly operating. ThisVenturi unit pushes the entrained material up through conduit 76 to thecommunicating conduits (not shown). The fluidizer assembly 60 isoperated for a period of time determined by the setting of timer T3.This is initially regulated so as to accommodate the size of chamber 10and the type of material. At the end of the timed fluidizing period, thechamber is scoured and practically clear of the granular material. Itwill be realized that, as the sand is removed from the fluidizingchamber, the level falls to a point near the bottom of apron 68 of thenozzle head, to expose the nozzle head. The downward conical blast ofair erodes the sand away and scours the walls, drawing the material awayfrom the base of the standpipe and also helically swirling it out of theperipheral corner juncture between the bottom 13 and walls 11. Timer T3times out approximately 3 to seconds prior to timing out of timer T1, sothat the fluidizer is shut off a few seconds prior to opening of inletvalve head 32. During this 3 to 5 second interval, since the positivepressure is no longer applied through the fluidizer, and since Venturiunit 80 operates continuously, this Venturi unit applies a continuousnegative pressure into opening 74, to decrease the positive pressure inthe fluidizing chamber down to atmospheric or slightly above. Thus, whentimer T1 times out and causes solenoid valve 112 to shift to openconduit 51 for lowering cylinder 40 and opening the receiving throatinto chamber 10, no back pressure will blow the sand back up through thehopper into the atmosphere. Further, if a very slight residual positivepressure does remain in fluidizing chamber 10, the slight positivepressure is vented through resilient valve means 90 which is allowed toopen simultaneously with opening of valve head 32. Thus, the granularmaterial can drop freely down into the chamber without initially blowingback. Moreover, since vent valve 90 remains open while valve head 32 isopen, the air contained in chamber is displaced by the dropping sand,and passes out through valve 90 without blowing back up through thehopper as was previously experienced. It has been found that the fillingtime can thus be accomplished in a matter of a few seconds rather thanrequiring a much longer time as was previously necessary. After a fewseconds, timer T2 times out to energize the four-way valve 112 to openit, allowing pressurized air to flow through line 52 to raise cylinder40 and close valve head 42 for the next fluidizing action. The cyclingcontrol of timers T2 and T3 are subsequently controlled each time bybeing energized when timer T1 times out.

It will be realized that even when valve head 32 is opening, to dropanother charge of granular material into the fluidizing chamber, theprevious charge of material is simultaneously being conveyed through theconduits to the points of demand in the foundry or other facilitybecause the Venturi unit 80 is still operating to push the sand upwardlythrough the conduit 76 and its communicate conduits not shown. Thispressure caused in the conduit, downstream of the ball check valvecauses the ball check to seal even more assuredly on its seat after thefluidizer is shut off. The unit 80 thus acts as a more or less secondaryconveyor when the fiuidizer is operating and the ball check is open, andacts as a primary conveyor when the fluidizer is shut off and the ballcheck closes.

In operation, the system has been found to work extremely effectively,rapidly, dependably, and to have a tremendous output in relation to itssize. Because of the novel venting system used in combination with theapparatus, the sand does not tend to bridge over the inlet throat to thefluidizing chamber. Therefore each opening of valve head 32 assures aproper charge of material being dropped into the fluidizing chamber.

It is conceivable that certain minor structural features of thisapparatus might be modified without departing from the concept. It isalso conceivable that certain additional advantages or features may beapparent to those in the art upon studying the foregoing specificationand specific preferred form shown. Hence, it is intended that theinvention is to be limited only by the scope of the appended claims andthe reasonably equivalent structures to those defined therein.

I claim:

1. Apparatus for fluidizing and transporting granular material,comprising: a hopper; a fluidizing chamber positioned below said hopper;a throat between said hopper and said fluidizing chamber for allowinggranular material to flow from said hopper into said fluidizing chamber;valve means for sealing off said throat at predetermined intervals; ahollow member extending upwardly into said fluidizing chamber, generallycentrally thereof, and having nozzle means on the upper end thereof,within said fluidizing chamber, with said nozzle means being positionedsubstantially from both the top and bottom of said fluidizing chambertangential apertures at the upper inner end of said hollow member andhood means at said upper end with a depending flange surrounding thatportion of said hollow member which contains said apertures to form, inconjunction with said hollow member, an annular, downwardly openingnozzle outlet, said tangential apertures and annular outlet cooperatingto cause fluidizing of the material in a swirling flow in said chamber,and directing an annular stream of air in a substantially downwarddirection to fluidize said granular material; compressed air supplymeans to said hollow member; and discharge outlet means radially offsetfrom said hollow member for conveying said fluidized granular materialfrom said fluidizing chamber, having port means for receiving thepneumatically fluidized material substantially below the point of airdischarge from said nozzle means.

2. The apparatus in claim 1 wherein said nozzle means is generallycentrally located in said chamber, and is capable of creating a positivepressure in said chamber; said outlet means comprises generally uprightconduit means spaced radially from said nozzle means with said portspaced below said nozzle means; and pneumatic conveying means on saidoutlet means arranged to create a negative pressure at said port to becooperative with said nozzle means to cause optimum material flow.

3. The apparatus in claim 1 wherein said control means includes multipleway valve means alternately communicating said pneumatic supplyconnection means to opposite ends of said cylinder through first andsecond conduit means to shift said throat valve means open and shut; andwherein bleed-off conduit means extends from said conduit means to saidventing valve means, to control the actuation thereof.

4. The apparatus in claim 1 wherein said nozzle means is centrallylocated in said chamber, and is capable of creating a positive pressurein said chamber; said outlet means comprises generally upright conduitmeans with said port spaced below said nozzle means; and pneumaticconveying means on said outlet means arranged to create a negativepressure at said port to be cooperative with said nozzle means to causeoptimum material flow.

5. The combination as set forth in claim 4 wherein said valve meanscomprises: a power unit capable of providing vertical motion; a shafthaving one end thereof attached to said power unit; a generallydome-shaped valve member having downwardly divergent walls attached tothe other end of said shaft, and a valve seat for receiving said member,said valve member being shiftable between an open lowered positionspaced below said valve seat in said fluidizing chamber, and a closedupper position against said valve seat.

6. The combination as set forth in claim in which said nozzle means ispositioned directly below said valve means, said dome shaped valvemember causing material flowing into said fluidizing chamber to bedeflected from falling directly on said nozzle means.

7. The apparatus in claim 3 wherein said chamber has a bottom surface,and said port is spaced from said surface such that the imaginaryperipheral area created by extending an imaginary surface from theperiphery of said port to said bottom surface is about equal to orslightly greater than the cross sectional area of said port.

8. The apparatus of claim 1 including, power operable venting valvemeans communicable with said chamber means and with ambient air outsidesaid chamber and shiftable between open and closed positions; poweroperating means operably connected with said trans-fer control valvemeans; and power control means operably associated with said poweroperating means and said power operable venting valve means adapted tovent said fiuidizing chamber with opening of said transfer control valvemeans.

9. The apparatus in claim 8 wherein said power op erating means for saidtransfer control valving' means is pneumatically operated throughconduit means, and said venting valve means is pneumatically operated bya bleedoif connection from said conduit means.

10. Apparatus for fluidizing and transporting granular material,comprising: a hopper; a fiuidizing chamber positioned below said hopper;a throat between said hopper and said fluidizing chamber for allowinggranular material to fiow from said hopper into said fiuidizing chamber;valve means for sealing off said throat at predetermined intervals;annular nozzle means within said fluidizing chamber, said nozzle meansbeing positioned substantially from both the top and bottom of saidfiuidizing chamber and directing an annular stream of air in asubstantially downward direction to fluidize said granular material;outlet means for conducting said fluidized granular material from saidfluidizing chamber, said outlet means having a port for receiving theair entrained material, said port being substantially below the point ofair discharge from said nozzle means; pneumatically operable ventingvalve means communicable with said fluidizing chamber and ambient airoutside said chamber; a pneumatic power cylinder operably connected tosaid throat valve means to open and close it; pneumatic supplyconnection means to said nozzle means, to said cylinder, and to saidventing valve means and control means operably associated with saidpneumatic supply connection means to cause said venting valve means toopen with actuation of said cylinder to open said throat valve means;said control means including multiple-way valve means alternatelycommunicating said pneumatic supply connection means to opposite ends ofsaid cylinder through first and second conduit means to shift saidthroat valve means open and shut; including bleed-off conduit meansextending from said conduit means to said venting valve means, tocontrol the actuation thereof; said pneumatic power cylinder extendingup into said hopper; a hollow member extending upwardly into saidfluidizing chamber, generally centrally thereof, and having said nozzlemeans at the upper end thereof, tangential apertures at the upper end ofsaid hollow member, and hood means at said upper end with a dependingflange surrounding that portion of said holloW member which containssaid apertures to form, in conjunction with said hollow member, anannular, downwardly opening nozzle outlet, said tangential apertures andannular outlet cooperating to cause fluidizing of the material in aswirling flow in said chamber; pneumatic conveying means on said outletmeans arranged to create a negative pressure at said port to becooperative with said nozzle means to cause optimum material fiow; andsaid control means including timer means to actuate said power cylinder,said multiple-way valve means, and said fluidizing nozzle means incontrolled relationship.

References Cited UNITED STATES PATENTS 780,330 11/ 1905 Egert 222-1931,216,146 2/1917 Lissauer 239-474 1,686,713 10/1928 Scott 302-252,652,175 9/1953 Davis 222-193 2,722,372 11/1955 Edwards 302-253,099,965 8/1963 Regencheit 302-25 3,101,159 8/1963 Fletcher 222-3,115,279 12/ 1963 Christensen et al 222-61 3,121,593 2/1964 McIlvaine302-53 3,189,061 6/1965 Stockel et al 222-193 3,278,451 10/ 19-66 Childset al. 222-193 WALTER SOBIN, Primary Examiner.

